The investment seeks to track the investment results (before fees and expenses) of the ICE BofAML US Taxable Municipal Securities Plus Index (the "underlying index"). The fund generally will invest at least 80% of its total assets in taxable municipal securities that comprise the underlying index. The underlying index is designed to track the performance of U.S. dollar-denominated taxable municipal debt publicly issued by U.S. states and territories, and their political subdivisions, in the U.S. market.